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1.
Leukocyte Trafficking via Lymphatic Vessels in Atherosclerosis.
Yeo, KP, Lim, HY, Angeli, V
Cells. 2021;(6)
Abstract
In recent years, lymphatic vessels have received increasing attention and our understanding of their development and functional roles in health and diseases has greatly improved. It has become clear that lymphatic vessels are critically involved in acute and chronic inflammation and its resolution by supporting the transport of immune cells, fluid, and macromolecules. As we will discuss in this review, the involvement of lymphatic vessels has been uncovered in atherosclerosis, a chronic inflammatory disease of medium- and large-sized arteries causing deadly cardiovascular complications worldwide. The progression of atherosclerosis is associated with morphological and functional alterations in lymphatic vessels draining the diseased artery. These defects in the lymphatic vasculature impact the inflammatory response in atherosclerosis by affecting immune cell trafficking, lymphoid neogenesis, and clearance of macromolecules in the arterial wall. Based on these new findings, we propose that targeting lymphatic function could be considered in conjunction with existing drugs as a treatment option for atherosclerosis.
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Selenocompounds and Sepsis: Redox Bypass Hypothesis for Early Diagnosis and Treatment: Part A-Early Acute Phase of Sepsis: An Extraordinary Redox Situation (Leukocyte/Endothelium Interaction Leading to Endothelial Damage).
Forceville, X, Van Antwerpen, P, Preiser, JC
Antioxidants & redox signaling. 2021;(2):113-138
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Abstract
Significance: Sepsis is a health disaster. In sepsis, an initial, beneficial local immune response against infection evolves rapidly into a generalized, dysregulated response or a state of chaos, leading to multiple organ failure. Use of life-sustaining supportive therapies creates an unnatural condition, enabling the complex cascades of the sepsis response to develop in patients who would otherwise die. Multiple attempts to control sepsis at an early stage have been unsuccessful. Recent Advances: Major events in early sepsis include activation and binding of leukocytes and endothelial cells in the microcirculation, damage of the endothelial surface layer (ESL), and a decrease in the plasma concentration of the antioxidant enzyme, selenoprotein-P. These events induce an increase in intracellular redox potential and lymphocyte apoptosis, whereas apoptosis is delayed in monocytes and neutrophils. They also induce endothelial mitochondrial and cell damage. Critical Issues: Neutrophil production increases dramatically, and aggressive immature forms are released. Leukocyte cross talk with other leukocytes and with damaged endothelial cells amplifies the inflammatory response. The release of large quantities of reactive oxygen, halogen, and nitrogen species as a result of the leukocyte respiratory burst, endothelial mitochondrial damage, and ischemia/reperfusion processes, along with the marked decrease in selenoprotein-P concentrations, leads to peroxynitrite damage of the ESL, reducing flow and damaging the endothelial barrier. Future Directions: Endothelial barrier damage by activated leukocytes is a time-sensitive event in sepsis, occurring within hours and representing the first step toward organ failure and death. Reducing or stopping this event is necessary before irreversible damage occurs.
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Sustaining efficient immune functions with regular physical exercise in the COVID-19 era and beyond.
Furtado, GE, Letieri, RV, Caldo-Silva, A, Sardão, VA, Teixeira, AM, de Barros, MP, Vieira, RP, Bachi, ALL
European journal of clinical investigation. 2021;(5):e13485
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Abstract
The new coronavirus (SARS-CoV-2) appearance in Wuhan, China, did rise the new virus disease (COVID-19), which spread globally in a short time, leading the World Health Organization to declare a new global pandemic. To contain and mitigate the spread of SARS-CoV-2, specific public health procedures were implemented in virtually all countries, with a significant impact on society, making it difficult to keep the regular practice of physical activity. It is widely accepted that an active lifestyle contributes to the improvement of general health and preservation of cardiovascular, respiratory, osteo-muscular and immune system capacities. The positive effects of regular physical activity on the immune system have emerged as a pivotal trigger of general health, underlying the beneficial effects of physical activity on multiple physiological systems. Accordingly, recent studies have already pointed out the negative impact of physical inactivity caused by the social isolation imposed by the public sanitary authorities due to COVID-19. Nevertheless, there are still no current narrative reviews evaluating the real impact of COVID-19 on active lifestyle or even discussing the possible beneficial effects of exercise-promoted immune upgrade against the severity or progression of COVID-19. Based on the consensus in the scientific literature, in this review, we discuss how an exercise adherence could adequately improve immune responses in times of the 'COVID-19 Era and beyond'.
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COVID-19 and hydatidiform mole.
Abbas, AM, Ahmed, L, Salem, AS, Elsamman, SH, Refai, A, Fathy, SK, Ahmed, OA, Shalotut, AS, AbdelWahab, RA
American journal of reproductive immunology (New York, N.Y. : 1989). 2020;(5):e13310
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Abstract
The emergence of coronavirus disease 2019 (COVID-19) as a pandemic threatens the entire world resulting in severe consequences for people's health. Pregnant patients with COVID-19 had immune dysregulation that could result in abnormal pregnancy outcomes such as hydatidiform mole (HM), recurrent pregnancy loss, and early-onset preeclampsia. In this article, we tried to summarize the possible association between COVID-19 and the HM's development by reviewing the role of NOD-Like Receptor (NLR) Family Pyrin Domain Containing 7 (NLRP7), cytokines, zinc, and leukocytes in the pathogenesis of HM.
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Inflammation and the Intestinal Barrier: Leukocyte-Epithelial Cell Interactions, Cell Junction Remodeling, and Mucosal Repair.
Luissint, AC, Parkos, CA, Nusrat, A
Gastroenterology. 2016;(4):616-32
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Abstract
The intestinal tract is lined by a single layer of columnar epithelial cells that forms a dynamic, permeable barrier allowing for selective absorption of nutrients, while restricting access to pathogens and food-borne antigens. Precise regulation of epithelial barrier function is therefore required for maintaining mucosal homeostasis and depends, in part, on barrier-forming elements within the epithelium and a balance between pro- and anti-inflammatory factors in the mucosa. Pathologic states, such as inflammatory bowel disease, are associated with a leaky epithelial barrier, resulting in excessive exposure to microbial antigens, recruitment of leukocytes, release of soluble mediators, and ultimately mucosal damage. An inflammatory microenvironment affects epithelial barrier properties and mucosal homeostasis by altering the structure and function of epithelial intercellular junctions through direct and indirect mechanisms. We review our current understanding of complex interactions between the intestinal epithelium and immune cells, with a focus on pathologic mucosal inflammation and mechanisms of epithelial repair. We discuss leukocyte-epithelial interactions, as well as inflammatory mediators that affect the epithelial barrier and mucosal repair. Increased knowledge of communication networks between the epithelium and immune system will lead to tissue-specific strategies for treating pathologic intestinal inflammation.
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Molecular Imaging of Inflammation: Current Status.
Hammoud, DA
Journal of nuclear medicine : official publication, Society of Nuclear Medicine. 2016;(8):1161-5
Abstract
The ability to image inflammation in vivo can improve our understanding of the pathophysiology underlying various disease etiologies, including cancer, atherosclerosis, and neurodegeneration. A great wealth of preclinical and translational research has been and is currently being developed to decipher the involvement of the immune system in disease pathophysiology, quantify the course of a disease, and visualize the potential detrimental effects of excessive inflammation. Down the road, the ultimate goal is to have clinical noninvasive in vivo imaging biomarkers of inflammation that will help diagnose disease, establish prognosis, and gauge response to preventative and therapeutic strategies.
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Metallothionein and Zinc Transporter Expression in Circulating Human Blood Cells as Biomarkers of Zinc Status: a Systematic Review.
Hennigar, SR, Kelley, AM, McClung, JP
Advances in nutrition (Bethesda, Md.). 2016;(4):735-46
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Abstract
Zinc is an essential nutrient for humans; however, a sensitive biomarker to assess zinc status has not been identified. The objective of this systematic review was to compile and assess studies that determined zinc transporter and/or metallothionein expression in various blood cell types and to determine their reliability and sensitivity to changes in dietary zinc. Sixteen studies were identified that determined the expression of zrt-, irt-like protein (ZIP) 1 [solute carrier family (SLC) 39A1], ZIP3 (SLC39A3), ZIP5 (SLC39A5), ZIP6 (SLC39A6), ZIP7 (SLC39A7), ZIP8 (SLC39A8), ZIP10 (SLC39A10), ZIP14 (SLC39A14), zinc transporter (ZnT)1 (SLC30A1), ZnT2 (SLC30A2), ZnT4 (SLC30A4), ZnT5 (SLC30A5), ZnT6 (SLC30A6), ZnT7 (SLC30A7), ZnT9 (SLC30A9), and/or metallothionein in various blood cells isolated from healthy adult men and women in response to zinc supplementation or depletion. Cell types included leukocytes, peripheral blood mononuclear cells, T lymphocytes, monocytes, and erythrocytes. ZIP1, ZnT1, and metallothionein were the most commonly measured proteins. Changes in ZIP1 and ZnT1 in response to zinc supplementation or depletion were not consistent across studies. Leukocyte metallothionein decreased with zinc depletion (-39% change from baseline, <5 mg Zn/d, n = 2 studies) and increased with zinc supplementation in a dose-dependent manner (35%, 15-22 mg Zn/d, n = 7 studies; 267%, 50 mg Zn/d, n = 2 studies) and at the earliest time points measured; however, no change or delayed response was observed in metallothionein in erythrocytes. A greater percentage of studies demonstrated that metallothionein in leukocyte subtypes was a more reliable (100%, n = 12; 69%, n = 16) and responsive (92%, n = 12; 82%, n = 11) indicator of zinc exposure than was plasma zinc, respectively. In conclusion, current evidence indicates that metallothionein in leukocyte subtypes may be a component in determining zinc status.
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Systemic changes in neovascular age-related macular degeneration.
Singh, A
Danish medical journal. 2014;(6):B4872
Abstract
Age-related macular degeneration (AMD) is a leading cause of visual impairment in the aged population worldwide. The mechanisms underlying this multifactorial and heterogenic disease are complex and incompletely understood. There is increasing evidence to suggest that regulatory differences in the immune system are involved in the development of the various subtypes of AMD. The purpose of this thesis was to identify some of these potential differences in patients with early or late (wet, dry, or fibrotic) AMD. Specifically, we sought to determine differences in 1) expression of regulators of the complement pathway (CD46, CD55, and CD59) on circulating leukocytes; 2) expression of microglia-inhibitory proteins (CD200 and CD200R) on circulating leukocytes; and 3) plasma concentrations of 25-hydroxyvitamin D, a factor known to inhibit angiogenesis, fibrosis, inflammation, and oxidation. All participants underwent a semi-structured interview and detailed retinal imaging. Fresh venous blood was obtained and the frequency of cells expressing the proteins in question was determined using flow cytometry. Plasma 25-hydroxyvitamin D was measured using liquid chromatography-tandem mass spectrometry. Also, genotyping as performed in order to determine the frequency of certain single-nucleotide polymorphisms in the vitamin D metabolism. Patients with wet AMD were found to have statistically significant lower frequencies of CD46 and CD59 on CD14+monocytes and higher frequencies of CD200 on CD11b+ monocytes compared to control individuals without AMD (p = 0.0070 and p = 0.047, respectively). Moreover, we found a lower frequency of CD46 on CD45+lymphocytes in patients with wet AMD and subretinal fibrosis compared to patients with wet AMD without fibrosis (p = 0.010). Vitamin D status was not different across AMD subgroups; however, the presence of subretinal fibrosis in patients with wet AMD was associated with a statistically significant lower concentration of 25-hydroxyvitamin D (p < 0.001). Our results suggest that inadequate systemic immune modulation is an important pathogenic mechanism in the aetiology of AMD. Moreover, some differences in protein expression and vitamin D status appear to be related to the phenotypical diversity of AMD, proposing that different mechanisms may underlie the different subtypes of AMD.
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Immune responses to resistance exercise.
Freidenreich, DJ, Volek, JS
Exercise immunology review. 2012;:8-41
Abstract
Resistance exercise induces changes in leukocyte redistribution, phenotypical surface expression and leukocyte functionality. Several factors have been shown to alter the temporal pattern and/or magnitude of response including manipulation of acute program variables, the aging process, and nutritional supplementation. Rest period length and load can modify the temporal pattern and/or magnitude of leukocytosis post exercise. Aging diminishes both the duration and magnitude of the post exercise leukocytosis and reduces leukocyte functionality. The few studies that assessed the effects of nutritional supplements (e.g., carbohydrate, whey protein, caffeine) peri-resistance exercise showed minimal effects on leukocyte responses. Sex differences exist in the timing and magnitude of leukocyte infiltration into skeletal muscle. The immune response to resistance exercise is only a small part of the recovery paradigm. A better understanding of how acute program variables and other factors such as aging, sex and nutritional supplementation affect the immune response to resistance exercise is important in the context of improving recovery, performance and health.
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Regulation of inflammation by short chain fatty acids.
Vinolo, MA, Rodrigues, HG, Nachbar, RT, Curi, R
Nutrients. 2011;(10):858-76
Abstract
The short chain fatty acids (SCFAs) acetate (C(2)), propionate (C(3)) and butyrate (C(4)) are the main metabolic products of anaerobic bacteria fermentation in the intestine. In addition to their important role as fuel for intestinal epithelial cells, SCFAs modulate different processes in the gastrointestinal (GI) tract such as electrolyte and water absorption. These fatty acids have been recognized as potential mediators involved in the effects of gut microbiota on intestinal immune function. SCFAs act on leukocytes and endothelial cells through at least two mechanisms: activation of GPCRs (GPR41 and GPR43) and inhibiton of histone deacetylase (HDAC). SCFAs regulate several leukocyte functions including production of cytokines (TNF-α, IL-2, IL-6 and IL-10), eicosanoids and chemokines (e.g., MCP-1 and CINC-2). The ability of leukocytes to migrate to the foci of inflammation and to destroy microbial pathogens also seems to be affected by the SCFAs. In this review, the latest research that describes how SCFAs regulate the inflammatory process is presented. The effects of these fatty acids on isolated cells (leukocytes, endothelial and intestinal epithelial cells) and, particularly, on the recruitment and activation of leukocytes are discussed. Therapeutic application of these fatty acids for the treatment of inflammatory pathologies is also highlighted.